The treatment or coating of active substances, such as drugs, vitamins, minerals, and the like, has resulted in a variety of orally-administrable dosage forms. One principal goal in the formulation of such dosage forms is often the slow and sustained release of the active ingredient over a relatively long period of time, e.g., sev eral hours. Such sustained release profiles generally afford such benefits as maximum dosage delivery with minimal compliance problems since, in the case of drugs, the patient need not take repeated dosages in order to ensure long-term drug release.